This is a randomized, stratified, parallel-group, double-blind trial comparing placebo with two doses of SR 57746A and Riluzole in 1200 individuals aged 18-75 years with diagonsis of ALS across centers in North America and Europe. There will be 13 visits over 18 months. Paricipants are allowed to be on riluzole which is the only approved treatment for ALS. Patients will continue to be followed by their priviate physician or in the Washington University Neuromuscular clinic for their regular medical/ALS care.